2,4-dihaloanilines in general, and 4-bromo-2-fluoroaniline in particular, are useful, inter alia, in the preparation of pharmaceutical and agricultural chemicals. The preparation of these useful chemical intermediates, until now, has been cumbersome and expensive. Prior art processes for the production of 4-bromo-2-fluoroaniline, for example, may require the use of expensive and/or difficult-to-obtain brominating agents.
One process for the preparation of 4-bromo-2-fluoroaniline (and its use in the preparation of arylpropionic acids) is taught in U.S. Pat. No. 4,443,631 to Padilla, issued Apr. 17, 1984. 1,3-dibromo-5,5-dimethylhydantoin in dimethylformamide (DMF) is prepared under nitrogen and is added to a solution of 2-fluoroaniline in DMF maintained at -34.degree. to -23.degree. C. with a dry ice-acetone bath. Other brominating agents reportedly useful are N-bromoamides or -imides such as N-bromoacetamide or N-bromosuccinimide.
U.S. Pat. No. 3,987,057 (Goddard, Oct. 19, 1976) references the production of 4-bromo-2-fluoroaniline from 2-fluoroaniline and N-bromo-succinimide.
U.S. Pat. No. 4,138,242 (Goddard, Feb. 6, 1979) relates to herbicidal compounds and their preparation from 4-chloro-2-fluoroaniline. The 4-chloro-2-fluoroaniline is prepared through the chlorination of 2-fluoroacetanilide to yield 4-chloro-2-fluoroacetanilide and the subsequent formation of the desired aniline.
It is an object of the present invention to provide a simple, safe and relatively inexpensive process for the production of 2,4-dihalo-anilines.